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Date: Wed, 28 Nov 2007 09:41:22 -0600 From: Larry Finger <larry.finger@...inger.net> To: Andreas Schwab <schwab@...e.de> CC: LKML <linux-kernel@...r.kernel.org> Subject: Re: Question regarding mutex locking Andreas Schwab wrote: > Larry Finger <Larry.Finger@...inger.net> writes: > >> If a particular routine needs to lock a mutex, but it may be entered with that mutex already locked, >> would the following code be SMP safe? >> >> hold_lock = mutex_trylock() >> >> ... >> >> if (hold_lock) >> mutex_unlock() > > When two CPUs may enter the critical region at the same time, what is > the point of the mutex? Also, the first CPU may unlock the mutex while > the second one is still inside the critical region. Thank you for that answer. I think that I'm finally beginning to understand. Larry - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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